Question

The first term of an arithmetic sequence is 4 and the tenth term is 67.

What is the common difference? Show your work or explain your answer.

Answer 1

d = 7

Explanation:

The nth term of an arithmetic sequence is

`a_(n)` = a₁ + (n - 1)d

where a₁ is the first term and d the common difference

Give a₁₀ = 67 and a₁ = 4 , then

a₁ + 9d = 67

4 + 9d = 67 ( subtract 4 from both sides )

9d = 63 ( divide both sides by 9 )

d = 7